mc68hc08ln56 Freescale Semiconductor, Inc, mc68hc08ln56 Datasheet - Page 140

• Manufacturer Part Number: mc68hc08ln56
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Serial Communications Interface Module (SCI)
12.4.2.1 Character Length
The transmitter can accommodate either 8-bit or 9-bit data. The state of the M bit in SCI control register 1
(SCC1) determines character length. When transmitting 9-bit data, bit T8 in SCI control register 3 (SCC3)
is the ninth bit (bit 8).
12.4.2.2 Character Transmission
During an SCI transmission, the transmit shift register shifts a character out to the PTE5/TxD pin. The SCI
data register (SCDR) is the write-only buffer between the internal data bus and the transmit shift register.
To initiate an SCI transmission:
140
1. Enable the SCI by writing a logic one to the enable SCI bit (ENSCI) in SCI control register 1
2. Enable the transmitter by writing a logic one to the transmitter enable bit (TE) in SCI control
3. Clear the SCI transmitter empty bit by first reading SCI status register 1 (SCS1) and then writing
4. Repeat step 3 for each subsequent transmission.
SCI Baud Rate Register
SCI Control Register 1
SCI Control Register 2
SCI Control Register 3
(SCC1).
register 2 (SCC2).
to the SCDR. In a DMA transfer, the DMA automatically clears the SCTE bit by writing to the SCDR.
Register Name
SCI Status Register 1
SCI Data Register
(SCDR)
(SCBR)
(SCC1)
(SCC2)
(SCC3)
Register:
Address:
(SCS1)
MC68HC08LN56 • MC68HC708LN56 General Release Specification, Rev. 2.1
Figure 12-5. SCI Transmitter I/O Register Summary
Reset:
Reset:
Reset:
Reset:
Reset:
Reset:
Read:
Read:
Read:
Read:
Read:
Read:
Write:
Write:
Write:
Write:
Write:
Write:
Table 12-3. SCI Transmitter I/O Address Summary
LOOPS
SCTIE
SCTE
Bit 7
$0013
SCC1
R8
R7
T7
U
0
0
1
0
= Unimplemented
ENSCI
TCIE
TC
R6
T8
T6
U
6
0
0
1
0
$0014
SCC2
DMARE
SCRIE
TXINV
SCRF
SCP1
R5
T5
5
0
0
0
0
0
$0015
SCC3
U = Unaffected
DMATE
Unaffected by reset
SCP0
IDLE
ILIE
R4
T4
4
M
0
0
0
0
0
$0016
SCS1
WAKE
ORIE
OR
TE
R3
T3
3
R
0
0
0
0
0
SCDR
$0018
R = Reserved
SCR2
NEIE
ILTY
RE
NF
R2
T2
2
0
0
0
0
0
Freescale Semiconductor
SCBR
$0019
SCR1
RWU
FEIE
PEN
FE
R1
T1
1
0
0
0
0
0
Bit 0
SCR0
PEIE
PTY
SBK
PE
R0
T0
0
0
0
0
0